How much depends on what lawns are replaced with
                                
                                
                                    (Newser) -
                                    The typical California home's biggest area of water usage is beyond its four walls:  its outdoor landscaping . So in the face of drought, tens of thousands of Los Angeles homeowners made a change last summer, reports the  Times , swapping their grass for artificial turf, gravel, or drought-tolerant shrubs. And...